|[List of appearances]|
The Book of Monsters is a sentient book owned by Jestro, who used it to conjure monsters in his bid to exact vengeance on the Kingdom of Knighton. Claiming to have been a possession of the evil sorceror Monstrox, it goads Jestro into deepening his evil while searching for cursed spell books to increase its own power; by eating these books, the Book of Monsters becomes larger and more powerful, able to use different magics and summon a wider variety of monster minions.
Eventually, it is revealed that the Book of Monsters is Monstrox himself, having been trapped in the form of a book by his old nemesis Merlok. Monstrox's power was divided between the other spell books and cast across the land of Knighton in a bid to keep him from ever regaining his true strength; by corrupting Jestro, Monstrox hopes to restore his full power and escape his prison by possessing a living host. His plans were thwarted by the Nexo Knights, who redeemed Jestro and seemingly destroyed the Book of Monsters; however, Monstrox's spirit survived in the form of a living storm cloud, which he used to re-corrupt Jestro and create a new army of monsters from stone statues.
- Book of Monsters
Gallery of variants